Adding all of the functions

packages/color-helpers/src/calculations/LICENSE.md

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+All documents in this Directory are licensed by contributors
+under the 
+[W3C Software and Document License](https://www.w3.org/Consortium/Legal/copyright-software).

packages/color-helpers/src/calculations/binary-search-gamut.ts

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+import { clip } from 'utils/clip';
+import { OKLCH_to_OKLab } from 'conversions/oklch-to-oklab';
+import { deltaEOK } from 'calculations/deltaEOK';
+
+/**
+ * @license W3C https://www.w3.org/Consortium/Legal/2015/copyright-software-and-document
+ *
+ * @copyright This software or document includes material copied from or derived from https://github.com/w3c/csswg-drafts/blob/main/css-color-4/map-gamut.js. Copyright © 2022 W3C® (MIT, ERCIM, Keio, Beihang).
+ */
+export function binarySearchGamut(
+	startOKLCH: Color,
+	toDestination: (x: Color) => Color,
+	fromDestination: (x: Color) => Color,
+): Color {
+	let min = 0;
+	let max = startOKLCH[1];
+	const current = startOKLCH;
+
+	while (max - min > 0.0001) {
+		const clipped = clip(toDestination(current));
+		const deltaE = deltaEOK(OKLCH_to_OKLab(current), OKLCH_to_OKLab(fromDestination(clipped)));
+		// are we inside the gamut (or very close to the boundary, outside)
+		if (deltaE - 0.02 < 0.0001) {
+			min = current[1];
+		} else {
+			max = current[1];
+		}
+		// binary search
+		current[1] = (max + min) / 2;
+	}
+
+	return clip(toDestination([...current]));
+}

packages/color-helpers/src/calculations/contrast.ts

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+/**
+ * Return WCAG 2.1 contrast ratio for two sRGB values given as arrays
+ *
+ * of 0.0 to 1.0
+ * @license W3C https://www.w3.org/Consortium/Legal/2015/copyright-software-and-document
+ *
+ * @copyright This software or document includes material copied from or derived from https://github.com/w3c/csswg-drafts/blob/main/css-color-4/utilities.js. Copyright © 2022 W3C® (MIT, ERCIM, Keio, Beihang).
+ *
+ * @see https://github.com/w3c/csswg-drafts/blob/main/css-color-4/utilities.js
+ * @see https://www.w3.org/TR/WCAG21/#dfn-contrast-ratio
+ */
+import { sRGB_to_luminance } from 'conversions/srgb-to-luminance';
+
+export function contrast(RGB1: Color, RGB2: Color): number {
+	const L1 = sRGB_to_luminance(RGB1);
+	const L2 = sRGB_to_luminance(RGB2);
+
+	if (L1 > L2) {
+		return (L1 + 0.05) / (L2 + 0.05);
+	}
+
+	return (L2 + 0.05) / (L1 + 0.05);
+}

packages/color-helpers/src/calculations/deltaEOK.ts

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+/**
+ * @description Calculate deltaE OK which is the simple root sum of squares
+ *
+ * @license W3C https://www.w3.org/Consortium/Legal/2015/copyright-software-and-document
+ *
+ * @copyright This software or document includes material copied from or derived from https://github.com/w3c/csswg-drafts/blob/main/css-color-4/deltaEOK.js. Copyright © 2022 W3C® (MIT, ERCIM, Keio, Beihang).
+ *
+ * @see https://github.com/w3c/csswg-drafts/blob/main/css-color-4/deltaEOK.js
+ */
+export function deltaEOK(reference: Color, sample: Color): number {
+	// Given reference and sample are both in OKLab
+	const [L1, a1, b1] = reference;
+	const [L2, a2, b2] = sample;
+	const ΔL = L1 - L2;
+	const Δa = a1 - a2;
+	const Δb = b1 - b2;
+	return Math.sqrt(ΔL ** 2 + Δa ** 2 + Δb ** 2);
+}

packages/color-helpers/src/calculations/map-gamut.ts

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+import { binarySearchGamut } from 'calculations/binary-search-gamut';
+
+/**
+ * @license W3C https://www.w3.org/Consortium/Legal/2015/copyright-software-and-document
+ *
+ * @copyright This software or document includes material copied from or derived from https://github.com/w3c/csswg-drafts/blob/main/css-color-4/map-gamut.js. Copyright © 2022 W3C® (MIT, ERCIM, Keio, Beihang).
+ */
+export function mapGamut(startOKLCH: Color, toDestination: (x: Color) => Color, fromDestination: (x: Color) => Color): Color {
+	return binarySearchGamut(startOKLCH, toDestination, fromDestination);
+}

packages/color-helpers/src/calculations/multiply-matrices.ts

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+/**
+ * Simple matrix (and vector) multiplication
+ * Warning: No error handling for incompatible dimensions!
+ * @author Lea Verou 2020 MIT License
+ *
+ * @license W3C https://www.w3.org/Consortium/Legal/2015/copyright-software-and-document
+ *
+ * @copyright This software or document includes material copied from or derived from https://github.com/w3c/csswg-drafts/blob/main/css-color-4/multiply-matrices.js. Copyright © 2022 W3C® (MIT, ERCIM, Keio, Beihang).
+ *
+ * @see https://github.com/w3c/csswg-drafts/blob/main/css-color-4/multiply-matrices.js
+ */
+// A is m x n. B is n x p. product is m x p.
+export function multiplyMatrices(a: Array<Array<number>> | Array<number>, b: Array<Array<number>> | Array<number>): Array<Array<number>> | Array<number> {
+	const m = a.length;
+
+	let A: Array<Array<number>>;
+	if (!Array.isArray(a[0])) {
+		// A is vector, convert to [[a, b, c, ...]]
+		A = [a as Array<number>];
+	} else {
+		A = a as Array<Array<number>>;
+	}
+
+	let B: Array<Array<number>>;
+	if (!Array.isArray(b[0])) {
+		// B is vector, convert to [[a], [b], [c], ...]]
+		B = (b as Array<number>).map(x => [x]);
+	}
+
+	const p = B[0].length;
+	const B_cols = B[0].map((_, i) => B.map(x => x[i])); // transpose B
+	let product: Array<Array<number>> | Array<number> = A.map(row => B_cols.map(col => {
+		if (!Array.isArray(row)) {
+			return col.reduce((d, f) => d + f * row, 0);
+		}
+
+		return row.reduce((d, f, i) => d + f * (col[i] || 0), 0);
+	}));
+
+	if (m === 1) {
+		product = product[0]; // Avoid [[a, b, c, ...]]
+	}
+
+	if (p === 1) {
+		return product.map(x => x[0]); // Avoid [[a], [b], [c], ...]]
+	}
+
+	return product;
+}

packages/color-helpers/src/calculations/polar-premultiply.ts

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+/**
+ * Given a color in a cylindical polar colorspace and an alpha value
+ * return the premultiplied form. The index says which entry in the
+ * color array corresponds to hue angle for example, in OKLCH it
+ * would be 2 while in HSL it would be 0
+ *
+ * @param color
+ * @param alpha
+ * @param hueIndex
+ *
+ * @license W3C https://www.w3.org/Consortium/Legal/2015/copyright-software-and-document
+ *
+ * @copyright This software or document includes material copied from or derived from https://github.com/w3c/csswg-drafts/blob/main/css-color-4/conversions.js. Copyright © 2022 W3C® (MIT, ERCIM, Keio, Beihang).
+ */
+export function polar_premultiply(color: Color, alpha: number, hueIndex: number): Color {
+	return color.map((c, i) => c * (hueIndex === i ? 1 : alpha)) as Color;
+}

packages/color-helpers/src/conversions/LICENSE.md

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+Some documents in this Directory are licensed by contributors
+under the 
+[W3C Software and Document License](https://www.w3.org/Consortium/Legal/copyright-software).

packages/color-helpers/src/conversions/a98-rgb-to-srgb.ts

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+import { lin_a98rgb } from 'conversions/lin-a98rgb';
+import { lin_a98rgb_to_XYZ } from 'conversions/lin-a98rgb-to-xyz';
+import { XYZ_to_OKLab } from 'conversions/xyz-to-oklab';
+import { OKLab_to_OKLCH } from 'conversions/oklab-to-oklch';
+import { XYZ_to_lin_sRGB } from 'conversions/xyz-to-lin-srgb';
+import { gam_sRGB } from 'conversions/gam-srgb';
+import { inGamut } from 'utils/in-gamut';
+import { clip } from 'utils/clip';
+import { mapGamut } from 'calculations/map-gamut';
+import { OKLab_to_XYZ } from 'conversions/oklab-to-xyz';
+import { lin_sRGB } from 'conversions/lin-srgb';
+import { lin_sRGB_to_XYZ } from 'conversions/lin-srgb-to-xyz';
+import { OKLCH_to_OKLab } from 'conversions/oklch-to-oklab';
+
+export function a98_RGB_to_sRGB(a98: Color): Color {
+	let conversion = a98.slice() as Color;
+
+	// https://www.w3.org/TR/css-color-4/#predefined-to-predefined
+	// https://www.w3.org/TR/css-color-4/#predefined-to-lab-oklab
+	conversion = lin_a98rgb(conversion);
+	conversion = lin_a98rgb_to_XYZ(conversion);
+
+	let oklch = conversion.slice() as Color;
+	oklch = XYZ_to_OKLab(oklch);
+	oklch = OKLab_to_OKLCH(oklch);
+	if (oklch[0] < 0.000001) {
+		oklch = [0, 0, 0] as Color;
+	}
+
+	if (oklch[0] > 0.999999) {
+		oklch = [1, 0, 0] as Color;
+	}
+
+	// 3. Convert from(D65 - adapted) CIE XYZ to linear RGB
+	conversion = XYZ_to_lin_sRGB(conversion);
+	// 4. Convert from linear - light RGB to RGB(do gamma encoding)
+	conversion = gam_sRGB(conversion);
+
+	if (inGamut(conversion)) {
+		return clip(conversion);
+	}
+
+	return mapGamut(oklch, (x: Color) => {
+		x = OKLCH_to_OKLab(x);
+		x = OKLab_to_XYZ(x);
+		x = XYZ_to_lin_sRGB(x);
+		return gam_sRGB(x);
+	}, (x: Color) => {
+		x = lin_sRGB(x);
+		x = lin_sRGB_to_XYZ(x);
+		x = XYZ_to_OKLab(x);
+		return OKLab_to_OKLCH(x);
+	});
+}

packages/color-helpers/src/conversions/cie-xyz-50-to-srgb.ts

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+import { XYZ_to_OKLab } from 'conversions/xyz-to-oklab';
+import { OKLab_to_OKLCH } from 'conversions/oklab-to-oklch';
+import { D50_to_D65 } from 'conversions/d50-to-d65';
+import { XYZ_to_lin_sRGB } from 'conversions/xyz-to-lin-srgb';
+import { gam_sRGB } from 'conversions/gam-srgb';
+import { inGamut } from 'utils/in-gamut';
+import { clip } from 'utils/clip';
+import { mapGamut } from 'calculations/map-gamut';
+import { OKLCH_to_OKLab } from 'conversions/oklch-to-oklab';
+import { OKLab_to_XYZ } from 'conversions/oklab-to-xyz';
+import { lin_sRGB } from 'conversions/lin-srgb';
+import { lin_sRGB_to_XYZ } from 'conversions/lin-srgb-to-xyz';
+
+export function cie_XYZ_50_to_sRGB(xyz: Color): Color {
+	let conversion = xyz.slice() as Color;
+
+	// https://www.w3.org/TR/css-color-4/#predefined-to-predefined
+	// https://www.w3.org/TR/css-color-4/#predefined-to-lab-oklab
+	conversion = D50_to_D65(conversion);
+
+	let oklch = conversion.slice() as Color;
+	oklch = XYZ_to_OKLab(oklch);
+	oklch = OKLab_to_OKLCH(oklch);
+	if (oklch[0] < 0.000001) {
+		oklch = [0, 0, 0] as Color;
+	}
+
+	if (oklch[0] > 0.999999) {
+		oklch = [1, 0, 0] as Color;
+	}
+
+	// 3. Convert from(D65 - adapted) CIE XYZ to linear RGB
+	conversion = XYZ_to_lin_sRGB(conversion);
+	// 4. Convert from linear - light RGB to RGB(do gamma encoding)
+	conversion = gam_sRGB(conversion);
+
+	if (inGamut(conversion)) {
+		return clip(conversion);
+	}
+
+	return mapGamut(oklch, (x: Color) => {
+		x = OKLCH_to_OKLab(x);
+		x = OKLab_to_XYZ(x);
+		x = XYZ_to_lin_sRGB(x);
+		return gam_sRGB(x);
+	}, (x: Color) => {
+		x = lin_sRGB(x);
+		x = lin_sRGB_to_XYZ(x);
+		x = XYZ_to_OKLab(x);
+		return OKLab_to_OKLCH(x);
+	});
+}

packages/color-helpers/src/conversions/cie-xyz-65-to-srgb.ts

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+import { XYZ_to_OKLab } from 'conversions/xyz-to-oklab';
+import { OKLab_to_OKLCH } from 'conversions/oklab-to-oklch';
+import { XYZ_to_lin_sRGB } from 'conversions/xyz-to-lin-srgb';
+import { gam_sRGB } from 'conversions/gam-srgb';
+import { inGamut } from 'utils/in-gamut';
+import { clip } from 'utils/clip';
+import { mapGamut } from 'calculations/map-gamut';
+import { OKLCH_to_OKLab } from 'conversions/oklch-to-oklab';
+import { OKLab_to_XYZ } from 'conversions/oklab-to-xyz';
+import { lin_sRGB } from 'conversions/lin-srgb';
+import { lin_sRGB_to_XYZ } from 'conversions/lin-srgb-to-xyz';
+
+export function cie_XYZ_65_to_sRGB(xyz: Color): Color {
+	let conversion = xyz.slice() as Color;
+
+	// https://www.w3.org/TR/css-color-4/#predefined-to-predefined
+	// https://www.w3.org/TR/css-color-4/#predefined-to-lab-oklab
+	let oklch = conversion.slice() as Color;
+	oklch = XYZ_to_OKLab(oklch);
+	oklch = OKLab_to_OKLCH(oklch);
+	if (oklch[0] < 0.000001) {
+		oklch = [0, 0, 0] as Color;
+	}
+
+	if (oklch[0] > 0.999999) {
+		oklch = [1, 0, 0] as Color;
+	}
+
+	// 3. Convert from(D65 - adapted) CIE XYZ to linear RGB
+	conversion = XYZ_to_lin_sRGB(conversion);
+	// 4. Convert from linear - light RGB to RGB(do gamma encoding)
+	conversion = gam_sRGB(conversion);
+
+	if (inGamut(conversion)) {
+		return clip(conversion);
+	}
+
+	return mapGamut(oklch, (x: Color) => {
+		x = OKLCH_to_OKLab(x);
+		x = OKLab_to_XYZ(x);
+		x = XYZ_to_lin_sRGB(x);
+		return gam_sRGB(x);
+	}, (x: Color) => {
+		x = lin_sRGB(x);
+		x = lin_sRGB_to_XYZ(x);
+		x = XYZ_to_OKLab(x);
+		return OKLab_to_OKLCH(x);
+	});
+}

packages/color-helpers/src/conversions/constants.ts

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+// standard white points, defined by 4-figure CIE x,y chromaticities
+export const D50 = [0.3457 / 0.3585, 1.00000, (1.0 - 0.3457 - 0.3585) / 0.3585];
+export const D65 = [0.3127 / 0.3290, 1.00000, (1.0 - 0.3127 - 0.3290) / 0.3290];

packages/color-helpers/src/conversions/d50-to-d65.ts

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+/**
+ * Bradford chromatic adaptation from D50 to D65
+ *
+ * @license W3C https://www.w3.org/Consortium/Legal/2015/copyright-software-and-document
+ *
+ * @copyright This software or document includes material copied from or derived from https://github.com/w3c/csswg-drafts/blob/main/css-color-4/conversions.js. Copyright © 2022 W3C® (MIT, ERCIM, Keio, Beihang).
+ */
+import { multiplyMatrices } from 'calculations/multiply-matrices';
+
+export function D50_to_D65(XYZ: Color): Color {
+	const M = [
+		[0.9554734527042182, -0.023098536874261423, 0.0632593086610217],
+		[-0.028369706963208136, 1.0099954580058226, 0.021041398966943008],
+		[0.012314001688319899, -0.020507696433477912, 1.3303659366080753],
+	];
+
+	return multiplyMatrices(M, XYZ) as Color;
+}

packages/color-helpers/src/conversions/d65-to-d50.ts

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+/**
+ * Bradford chromatic adaptation from D65 to D50
+ * @license W3C https://www.w3.org/Consortium/Legal/2015/copyright-software-and-document
+ *
+ * @copyright This software or document includes material copied from or derived from https://github.com/w3c/csswg-drafts/blob/main/css-color-4/conversions.js. Copyright © 2022 W3C® (MIT, ERCIM, Keio, Beihang).
+ *
+ * @see http://www.brucelindbloom.com/index.html?Eqn_ChromAdapt.html
+ */
+import { multiplyMatrices } from 'calculations/multiply-matrices';
+
+export function D65_to_D50(XYZ: Color): Color {
+	// The matrix below is the result of three operations:
+	// - convert from XYZ to retinal cone domain
+	// - scale components from one reference white to another
+	// - convert back to XYZ
+	const M = [
+		[1.0479298208405488, 0.022946793341019088, -0.05019222954313557],
+		[0.029627815688159344, 0.990434484573249, -0.01707382502938514],
+		[-0.009243058152591178, 0.015055144896577895, 0.7518742899580008],
+	];
+
+	return multiplyMatrices(M, XYZ) as Color;
+}

packages/color-helpers/src/conversions/gam-2020.ts

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+/**
+ * Convert an array of linear-light rec2020 RGB  in the range 0.0-1.0
+ * to gamma corrected form ITU-R BT.2020-2 p.4
+ *
+ * @license W3C https://www.w3.org/Consortium/Legal/2015/copyright-software-and-document
+ *
+ * @copyright This software or document includes material copied from or derived from https://github.com/w3c/csswg-drafts/blob/main/css-color-4/conversions.js. Copyright © 2022 W3C® (MIT, ERCIM, Keio, Beihang).
+ */
+export function gam_2020(RGB: Color): Color {
+	const α = 1.09929682680944;
+	const β = 0.018053968510807;
+
+	return RGB.map(function (val) {
+		const sign = val < 0 ? -1 : 1;
+		const abs = Math.abs(val);
+
+		if (abs > β) {
+			return sign * (α * Math.pow(abs, 0.45) - (α - 1));
+		}
+
+		return 4.5 * val;
+	}) as Color;
+}